Preeclampsia (PE) is one of the most serious diseases during pregnancy. Circular RNAs (circRNAs) are strongly related to the occurrence of preeclampsia. Herein, we aimed to explore the potential role and mechanism of circRNA oligophrenin 1 (circ-OPHN1; hsa_circ_0007445) in PE. Quantitative real-time polymerase chain reaction (qPCR) and western blot were utilized to detect gene expression levels. The biological behaviors of trophoblast cells were determined by 3-(4,5-dimethyl-2-thiazolyl) −2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry, transwell, and wound healing methods. The binding relationship between microRNA-558 (miR-558) and circ-OPHN1 or thrombospondin 2 (THBS2) was validated via dual-luciferase reporter assay. Circ-OPHN1 and THBS2 levels were enhanced, while miR-558 level was declined in PE placental tissues. Circ-OPHN1 or THBS2 overexpression hindered the proliferation, migration, and invasion of trophoblast cells. In addition, circ-OPHN1 sequestered miR-558 to regulate THBS2 expression, thereby repressing the growth and mobility of trophoblast cells. Circ-OPHN1 inhibited trophoblast cell proliferation, migration, and invasion through mediating miR-558/ THBS2 axis, providing a novel pathway for PE pathogenesis.